Modern electronics and optics require the large-scale integration of small building blocks, such as nanoparticles and nanowires, into specific two-/three-dimensional (2D/3D) architectures. For example, 3D optical communication pathways have been implemented by tuning inter-particle spacing among nanoscale-size components such that only coupled nanoparticles can exchange information to build up high-speed all-optical computation.
Deoxyribonucleic acid (DNA) molecules that readily fold into arbitrary shapes can be used for the fabrication of such 2D-3D architectures (e.g., nanoscale devices), through both DNA-directed self-assembly and nanopatterning processes. Recently, a pattern transfer process, known as DNA lithography, has been used to pattern inorganic substrates using DNA templates as masks. In general, a DNA mask is adsorbed on a substrate, and then the substrate is etched, resulting in a substrate patterned in the shape of the DNA mask. The chemical stability of DNA, however, is limited. To protect the DNA masks from the harsh chemical reaction conditions of etching, the masks are protected with a coating, such as, for example, a metal coating or an oxide coating.